Rhododendron 'Purple Gem' Dwarf, low, compact mound shape, growing 2–5″ a year. Masses of tiny blue-purple flowers in May. Very small blue-green leaves turn bronze in winter. New growth is bluish green. A Guy Nearing hybrid, sister to Rh. ‘Ramapo’. (-18°F, UM). Rhododendrons prefer rich, humusy, acidic soil that drains well. Sandy or dry soil, as well as heavy clay, should be amended before planting by adding peat moss, peat humus, or compost.